The present invention relates generally to a height control system for an automotive vehicle suspension system for controlling vehicle height and regulating. The vehicular body profile to improve vehicle driving stability. More specifically, the invention relates to a vehicle height control system capable of detecting failure of a vehicle height sensor monitoring vertical displacement of the corresponding portion of the vehicle body, and performing a fail-safe operation which insures driving safety even when the vehicle height sensor fails.
Various vehicle height control systems have been developed and proposed in recent years. Some such vehicle height control systems include a vehicle height sensor which monitors vertical displacement of the vehicle body relative to the vehicular wheels and performs automatic vehicle height control to suppress pitching, rolling and yawing of the vehicle body. These recently proposed vehicle height control systems hold the vehicle profile stable so as to ensure driving stability. In addition, such vehicle height control systems serve to hold the vehicle body at a desired height, which may be adjusted manually and/or automatically in accordance with vehicle driving conditions.
In order to control the vehicle height acurately, the vehicle body displacement relative to the vehicular wheels has to be monitored accurately. For this purpose, vehicle height sensors may be provided in the vehicular suspension system for monitoring the vertical displacement of the vehicle body relative to the vehicular wheels. As will be appreciated, the acuracy of the vehicle height sensors is essential to the vehicle height control operation. In other words, if one or more vehicle height sensors fails, the vehicle height control will not be able to hold the vehicle level or at the desired height. Failure of the vehicle height sensor is even dangerous, since it may lead to abnormal height adjustment.